In assembly line manufacturing of vehicles, it is desirable that line fittings in air conditioning systems be secured using a power nut driver rather than using a fastening method requiring a backup wrench to counteract the torque. For this reason, peanut or block type fittings are often used.
Various refrigerants, some of which present environmental concerns, have been used in air conditioning systems for vehicles. As a result, legislation has been passed by various governmental agencies of the United States and the European Union, requiring that air conditioning systems operate with substantially no refrigerant leaks.
Seal structures with metal seal fittings suitable for installation using a power nut driver have been used to militate against leaks in the air conditioning system. Such seal structures and related block fittings are described, for example, in Assignee's U.S. Pat. No. 7,621,568 to Schroeder et al., U.S. Pat. No. 8,104,773 to Schroeder et al., U.S. Pat. No. 8,523,244 to Schroeder et al.
It has been found that, in applications where the metal seal fittings are subjected to severe vibration, for example, when used in an engine mounted discharge line, a prying action may occur. It is believed that the prying action results from transverse dynamic loads, which are applied to the seal fitting by engine roll and related vibrations in operation. Undesirably, the prying action can result in a loss of clamp load, and degradation of the resulting metal seal joint, over time.
There is a continuing need for a block fitting for metal seal structures which stabilizes the seal joint against transverse dynamic loads. Desirably, the block fitting militates against the loss of clamp load and seal joint degradation, and facilitates a use of the metal seal structures in applications where the metal seal structures may be subject to severe vibration.